Effects of Welfare-enhancing System Changes on Environmental Impacts of Broiler and Egg Production18 February 2014
Welfare-friendly changes in chicken systems can be achieved without a compromise in their environmental impacts, according to a team of UK-based researchers. They compared battery and colony cages for laying hens and for broilers, a standard and lower stocking density, the latter with a heat exchanger.
The environmental impacts of two alternative UK broiler production systems that aim to improve bird welfare (a lower stocking density indoor system and the same system combined with heat exchangers for ventilation air) were compared with the baseline standard indoor system of broiler production by Ikka Leinonen of Newcastle University and co-authors there and and Cranfield University.
In a paper in Poultry Science, they go on to explain that the environmental impacts of egg production in the conventional battery cage system - banned in the European Union in 2012 - and its replacement, the enriched colony cage system, were compared.
All comparisons were based on data obtained from the UK poultry industry, and the life cycle assessment method from cradle to farm gate was applied in the analyses.
The results show that the lower density system slightly increased the global warming potential (GWP) of broiler production (by two per cent), compared with the standard indoor system, due to increased heating requirements.
However, when combined with the heat exchanger, the GWP was actually reduced by three per cent compared with the standard system.
Both alternative systems for broilers resulted in a reduction in the eutrophication potential - by up to eight per cent - and acidification potential by up to 10 per cent.
The results also showed that the colony cage system had eight per cent lower primary energy use and three per cent lower GWP than the baseline cage system, due to better energy use efficiency and slightly improved productivity.
There were only minor differences in the eutrophication and acidification potentials between different egg production systems.
The results suggest that welfare-friendly changes in chicken systems can be achieved without a compromise in their environmental impacts.
Leinonen I., A.G. Williams and I. Kyriazakis. 2014. The effects of welfare-enhancing system changes on the environmental impacts of broiler and egg production. Poultry Science. 93(2):256-266. doi: 10.3382/ps.2013-03252
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